The apparatus initially considered for producing the novel acid compound disclosed in my copending application was similar to the mixing apparatus disclosed in U.S. Pat. No. 4,208,375 to Max L. Bard dated June 17, 1980; however, after considerable research and experimentation, the Bard apparatus had to be modified and improved to obtain and withstand the temperatures and pressures during the reaction sequence and also the corrosive attack of the ammonia, sulfuric acid and aqueous reagents employed in producing the novel acid compound. More specifically, the apparatus of the present invention includes a first reactor having a venturi configuration. A rigid mixing deflector is mounted within the throat portion of the venturi and comprises a stem portion extending axially from the throat portion of the venturi toward the outlet thereof, the stem terminating in a pair of divergent fingers having an arcuate cross-section. The side wall of the venturi is provided with an inclined fitting through which ammonia is injected into the reactor in the vicinity of the divergent fingers.
A second reactor is provided downstream from the first reactor and comprises a titanium pipe having an inclined fitting extending through the side wall thereof. A portion of the inner end of the fitting extends into the pipe and forms a baffle to facilitate the injection of sulfuric acid through the fitting and the mixing thereof with the aqueous ammonia medium flowing from the first reactor. A shock absorber communicates with the second reactor to cushion the exothermic reaction between the ammonia and sulfuric acid.
The ammonia/sulfuric acid reaction mixture then flows to a vat similar to that disclosed in the aforementioned Bard patent wherein the pressure and temperature of the reaction medium are reduced.
A novel cooling tower is provided which communicates with the vat, whereby the acidic product from the vat can be further cooled and either recirculated to the vat or withdrawn from the system. The cooling tower includes a bundle of vertically extending tubes connected at each end to header plates, the connection of each tube to the respective header plate comprising a flared or expanded convex wall portion of the tube cooperating with a similarly configured concave groove formed in the header plate. The relatively hot acidic product is introduced into the lower end of the tube bundle through a pipe rigidly connected to the lower header plate and having a slip-joint O-ring seal assembly between the pipe and the end wall of the cooling tower housing through which cooling water circulates over the exterior of the tube bundle. The expansion joints between the tubes and header plates, and the slip-joint O-ring assembly facilitate the expansion and contraction of the cooling tower components during the process.